Turner syndrome

The Adult Endocrinology Clinic provides diagnosis and follow-up for adult patients with an endocrine disorder, that is, a condition affecting the secretion of a hormone (excessive or insufficient secretion) and/or the gland that secretes it. The department therefore manages conditions affecting the thyroid, parathyroid glands, adrenal glands, gonads (ovaries and testes) and pituitary gland.

Since 2016, the Endocrinology Department of Erasme Hospital, in partnership with the Queen Fabiola Children’s University Hospital (HUDERF) for paediatric care, has been part of ENDO-ERN (European Reference Network for Rare Endocrine Conditions), the European Reference Network for rare endocrine diseases.

The mission of this network is to improve access to high-quality care for patients with rare endocrine disorders. It supports clinical research and contributes to the creation of registries listing patients receiving follow-up for rare conditions, in order to promote the sharing of knowledge and the improvement of clinical practices.

The management of rare endocrine diseases is multidisciplinary. Regular consultations are organised to discuss complex cases with numerous specialists within our institution, as well as through virtual consultations with recognised European experts via the ENDO-ERN network or during international multidisciplinary consultation meetings (France).

Some endocrine diseases begin at birth or during childhood and require lifelong treatment and follow-up. Transition consultations have been provided for many years in collaboration with our paediatric colleagues at HUDERF, to ensure the smoothest possible transition from paediatric to adult care.

Turner syndrome is a genetic condition associated with an abnormality of the sex chromosomes. It affects approximately 25 to 50 girls per 100,000. It is characterised by the presence of one normal X chromosome and the complete or partial absence of the second X chromosome. When all cells present this abnormality, it is referred to as X monosomy (45,X). In some people, only a proportion of cells is affected; this is known as mosaicism. The manifestations of the condition may be more or less pronounced depending on the type of chromosomal abnormality, although the karyotype does not always make it possible to predict the severity of the condition or the risk of long-term complications.

The two main characteristics of Turner syndrome are:

• A short stature 
• Premature ovarian insufficiency, resulting in delayed or absent puberty, amenorrhoea (absence of menstrual periods) and, most often, infertility.

Turner syndrome may also be associated with other conditions requiring regular medical follow-up, including:

• Cardiovascular abnormalities (heart valve abnormalities, aortic involvement, high blood pressure);
• Abnormalities in the shape of the kidneys
• Overweight, obesity and/or diabetes
• Autoimmune diseases such as autoimmune thyroiditis 
• Recurrent ear infections with residual hearing loss

Some patients also have difficulties with certain types of learning and visuospatial difficulties.

The manifestations of the syndrome vary considerably from one person to another. Some patients have few clinical signs and therefore require less intensive medical follow-up, whereas others require multidisciplinary follow-up throughout their lives.

The diagnosis may be made at different stages of life, depending on the clinical manifestations. It may be suspected before birth, during an ultrasound scan showing certain suggestive abnormalities, or through non-invasive prenatal testing (NIPT). The diagnosis is then confirmed by chromosomal analysis performed on a chorionic villus sample or by amniocentesis.

After birth, the diagnosis is most often suspected in the presence of:

• A reduced growth rate or short stature during childhood;
• An absence of or delayed puberty during adolescence;
• Amenorrhoea or infertility during adolescence or adulthood.

Certain physical characteristics may suggest the diagnosis, such as the position of the ears, hairline, the presence of a shorter finger, and the shape of the eyes and neck. However, these signs are inconsistent and are often less suggestive than abnormalities of growth and pubertal development.

Recurrent ear infections, hearing loss, learning difficulties or the discovery of a heart abnormality may also lead to suspicion of the diagnosis.

The diagnosis is confirmed by a karyotype performed on a blood sample, which reveals the complete or partial absence of an X chromosome. A hormonal assessment is also performed to evaluate ovarian function, particularly by measuring oestradiol and other hormones related to ovarian function.

Care is multidisciplinary and individualised. It includes, in particular, growth hormone treatment to improve final height, hormone replacement therapy to induce and then maintain puberty, as well as regular monitoring of cardiovascular, endocrine, metabolic, hearing and bone-related complications. If they wish to have children, patients are referred to the fertility clinic to discuss the various options available to them and receive appropriate support.

Psychological, neuropsychological and/or speech therapy support may also be offered according to each patient’s needs.

Management of Turner syndrome is based on an individualised, person-centred approach. It includes:

• Specialised diagnostic assessment (clinical, hormonal and genetic) 
• Screening for, prevention and treatment of associated complications 
• Clear information provided to the patient and her family
• Medical, psychological and social support throughout life, when necessary

Depending on each patient’s needs, medical monitoring and treatment may include:

• Hormone replacement therapy (oestrogen-progestogen therapy from puberty until the usual age of menopause)
• Growth hormone treatment during childhood and adolescence
• Thyroid hormone treatment in the event of hypothyroidism
• Surgical procedures when necessary (particularly in cardiology or ENT) 
• Fertility preservation procedures when indicated 
• Regular monitoring of bone, metabolic and cardiovascular health
• Appropriate treatment of complications that may arise during follow-up, such as obesity, diabetes, high blood pressure or osteoporosis.

The aim is to support each patient in understanding her condition and treatment, in order to promote her long-term quality of life.

Multidisciplinary team – Erasme Hospital – H.U.B

Management of Turner syndrome is based on close collaboration between several specialists:

• Paediatric endocrinologists (from HUDERF, as part of the transition to adult care) and adult endocrinologists (Erasme Hospital);
• Geneticists: Dr Isabelle Vandernoot, Dr Isabelle Migeotte 
• Gynaecologists specialising in fertility: Prof. Anne Delbaere, Dr Mélodie Vander Borght, Dr Ozlem Okutman 
• Cardiologist: Prof. Antoine Bondue 
• ENT specialist: Dr Maxime Niesen 
• Psychologist and neuropsychologist: Marianne Rotsaert, Dr Hichem Slama 
• Psychiatrist: Prof. Oswald Pierre, 
• Social services: Denis Storme

Since 2015, a Turner Platform has been organised at Erasme Hospital. It enables patients to meet, during a single day, various specialists from the multidisciplinary team (endocrinologist, gynaecologist from the fertility clinic, cardiologist, ENT specialist and geneticist). This organisation facilitates coordinated, personalised and comprehensive care during a single visit.

Good adherence to treatment and regular medical follow-up are essential. It is important to comply with recommendations concerning treatments, screening examinations and monitoring for any complications.

Adopting a balanced diet and engaging in regular physical activity help reduce the risk of cardiovascular and metabolic complications.

A health passport, specifically designed for patients with Turner syndrome, is made available to them. It includes follow-up recommendations adapted to the different stages of life (childhood, adolescence and adulthood) and facilitates coordination of care.

If you have any questions or difficulties, the medical team remains your primary point of contact to adapt your care.

During adolescence, a gradual preparation for the transition to adult care is organised. This stage helps strengthen the young patient’s autonomy, ensure continuity of medical care and transfer all the necessary information to the specialised adult service. The transition is planned in collaboration with the patient, their family, and the paediatric and adult care teams.

Patients are treated by a certified adult endocrinologist. Hormone assays and genetic tests are performed in a specialised laboratory. An on-call service is available 24 hours a day. Our centre is actively committed to improving knowledge and care for patients with rare endocrine diseases. A local registry has been established. The centre actively contributes to an international database (International Turner Syndrome Registry) dedicated to Turner syndrome. The aim is to gain a better understanding of the disease, optimise follow-up practices, and compare management approaches between different specialised centres. The team receives ongoing training, participates in congresses and seminars, initiates and collaborates on studies, and publishes in the field of gonadal disorders. It also provides training and teaching for students and doctors in training.